package com.tedu.day02.oop;

/**
 *
 */
class A1

public class 多态 {
    public static void main(String[]args){
      /** B1 b=new B1();
        A1 a=b;
        a.tell1();
        a.tell2();

       */
      A1 a1=new B1();
      B1 b=(B1)a;
        b.tell1();
        b.tell2();
        b.tell3();

    }
}
